The present invention relates to an image processing system which connects a plurality of image forming apparatuses and an image processing apparatus that supplies image data and, more particularly, to an image processing system which connects an image processing apparatus and image forming apparatus to each other via a high-speed serial communication with a mechanism for assuring a predetermined data transfer rate, and its control method.
In recent years, in order to implement high-speed data transfer, high-speed serial communications such as IEEE1394, USB (UNIVERSAL SERIAL BUS), and the like are used in place of conventional asynchronous communication means. USB, IEEE1394, or the like has a mechanism for assuring a given data transfer rate such as the isochronous transfer mode in IEEE1394. In the isochronous transfer mode, a required number of channels that can transfer data are assured at prescribed cycle time intervals, and data are transferred via the assured channels. In this manner, an image processing system that transfers image data from an image processing apparatus such as a computer or the like to an image forming apparatus while assuring a data transfer rate corresponding to the processing performance of the apparatus can be built.
Assume that image data is sent from a single computer to a plurality of image forming apparatuses connected to that computer via isochronous communications such as high-speed serial communications so as to control them to form images in such conventional image processing system. In this case, each image forming apparatus must comprise a reception image memory for reliably receiving data sent from the computer, and its cost increases accordingly. For example, when one of the plurality of image forming apparatuses is not ready to print, if the computer begins to send data, the image forming apparatus which is not ready to print must save received data. Hence, the conventional image forming apparatus must have a memory for that purpose.